# Threaded standoffs, M2.5 and M3 (hex and round)

> What are the dimensions of M3 and M2.5 hex standoffs for mounting a PCB?

- Category: Hardware › Fasteners
- Kind: Hardware
- Basis: common vendor dimensions
- Page: https://xemstudio.com/objects/threaded-standoffs-metric/ · JSON: https://xemstudio.com/api/geometry?object=threaded-standoffs-metric · Plain text: https://xemstudio.com/objects/threaded-standoffs-metric/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); linked files under their publishers' licenses

## Notes

- M2.5 (Raspberry Pi) standoffs: 5 mm across flats; M3: 5.5 mm across flats. Lengths 3–40 mm in 1–5 mm steps; male-female adds a 6 mm stud.
- Pocket for a hex standoff in a print: AF + 0.2 mm.

## Sizes

| thread | width_af_mm | corner_mm | common_lengths_mm |
|---|---|---|---|
| M2.5 | 5 | 5.8 | 3, 5, 6, 8, 10, 12, 15, 20 |
| M3 | 5.5 | 6.4 | 5, 6, 8, 10, 12, 15, 20, 25, 30 |

## Where the files are

- McMaster-Carr: [Standoffs (free STEP/IGES/STL per part, for your own design use; no redistribution)](https://www.mcmaster.com/products/standoffs/) — STEP, IGES, STL, PDF — McMaster-Carr site terms: personal design use, no redistribution (verify at link)

## Free STEP/STL (16 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/threaded-standoffs-metric/index.json

- standoff-m2.5x5: [STEP](https://xemstudio.com/files/hardware/threaded-standoffs-metric/standoff-m2.5x5.step) · [STL](https://xemstudio.com/files/hardware/threaded-standoffs-metric/standoff-m2.5x5.stl) — hex standoff M2.5 × 5, female-female
- standoff-m2.5x6: [STEP](https://xemstudio.com/files/hardware/threaded-standoffs-metric/standoff-m2.5x6.step) · [STL](https://xemstudio.com/files/hardware/threaded-standoffs-metric/standoff-m2.5x6.stl) — hex standoff M2.5 × 6, female-female
- standoff-m2.5x8: [STEP](https://xemstudio.com/files/hardware/threaded-standoffs-metric/standoff-m2.5x8.step) · [STL](https://xemstudio.com/files/hardware/threaded-standoffs-metric/standoff-m2.5x8.stl) — hex standoff M2.5 × 8, female-female
- standoff-m2.5x10: [STEP](https://xemstudio.com/files/hardware/threaded-standoffs-metric/standoff-m2.5x10.step) · [STL](https://xemstudio.com/files/hardware/threaded-standoffs-metric/standoff-m2.5x10.stl) — hex standoff M2.5 × 10, female-female
- standoff-m2.5x12: [STEP](https://xemstudio.com/files/hardware/threaded-standoffs-metric/standoff-m2.5x12.step) · [STL](https://xemstudio.com/files/hardware/threaded-standoffs-metric/standoff-m2.5x12.stl) — hex standoff M2.5 × 12, female-female
- standoff-m2.5x15: [STEP](https://xemstudio.com/files/hardware/threaded-standoffs-metric/standoff-m2.5x15.step) · [STL](https://xemstudio.com/files/hardware/threaded-standoffs-metric/standoff-m2.5x15.stl) — hex standoff M2.5 × 15, female-female
- standoff-m2.5x20: [STEP](https://xemstudio.com/files/hardware/threaded-standoffs-metric/standoff-m2.5x20.step) · [STL](https://xemstudio.com/files/hardware/threaded-standoffs-metric/standoff-m2.5x20.stl) — hex standoff M2.5 × 20, female-female
- standoff-m3x5: [STEP](https://xemstudio.com/files/hardware/threaded-standoffs-metric/standoff-m3x5.step) · [STL](https://xemstudio.com/files/hardware/threaded-standoffs-metric/standoff-m3x5.stl) — hex standoff M3 × 5, female-female
- standoff-m3x6: [STEP](https://xemstudio.com/files/hardware/threaded-standoffs-metric/standoff-m3x6.step) · [STL](https://xemstudio.com/files/hardware/threaded-standoffs-metric/standoff-m3x6.stl) — hex standoff M3 × 6, female-female
- standoff-m3x8: [STEP](https://xemstudio.com/files/hardware/threaded-standoffs-metric/standoff-m3x8.step) · [STL](https://xemstudio.com/files/hardware/threaded-standoffs-metric/standoff-m3x8.stl) — hex standoff M3 × 8, female-female
- standoff-m3x10: [STEP](https://xemstudio.com/files/hardware/threaded-standoffs-metric/standoff-m3x10.step) · [STL](https://xemstudio.com/files/hardware/threaded-standoffs-metric/standoff-m3x10.stl) — hex standoff M3 × 10, female-female
- standoff-m3x12: [STEP](https://xemstudio.com/files/hardware/threaded-standoffs-metric/standoff-m3x12.step) · [STL](https://xemstudio.com/files/hardware/threaded-standoffs-metric/standoff-m3x12.stl) — hex standoff M3 × 12, female-female
- standoff-m3x15: [STEP](https://xemstudio.com/files/hardware/threaded-standoffs-metric/standoff-m3x15.step) · [STL](https://xemstudio.com/files/hardware/threaded-standoffs-metric/standoff-m3x15.stl) — hex standoff M3 × 15, female-female
- standoff-m3x20: [STEP](https://xemstudio.com/files/hardware/threaded-standoffs-metric/standoff-m3x20.step) · [STL](https://xemstudio.com/files/hardware/threaded-standoffs-metric/standoff-m3x20.stl) — hex standoff M3 × 20, female-female
- standoff-m3x25: [STEP](https://xemstudio.com/files/hardware/threaded-standoffs-metric/standoff-m3x25.step) · [STL](https://xemstudio.com/files/hardware/threaded-standoffs-metric/standoff-m3x25.stl) — hex standoff M3 × 25, female-female
- standoff-m3x30: [STEP](https://xemstudio.com/files/hardware/threaded-standoffs-metric/standoff-m3x30.step) · [STL](https://xemstudio.com/files/hardware/threaded-standoffs-metric/standoff-m3x30.stl) — hex standoff M3 × 30, female-female

## Questions

**What size standoff does a Raspberry Pi use?**

M2.5, 5 mm across flats. The Pi 4, Pi 5, Zero 2 W and Pico all mount on M2.5; common heights are 5, 6, 10 and 12 mm.

**What is the across-flats size of an M3 hex standoff?**

5.5 mm across flats, 6.4 mm across corners. Pocket in a print: 5.7 mm across flats.

## Fits with

- [Raspberry Pi 5](https://xemstudio.com/objects/raspberry-pi-5/)
- [Raspberry Pi 4 Model B](https://xemstudio.com/objects/raspberry-pi-4-b/)
- [Socket head cap screws, M2–M8 (ISO 4762 / DIN 912)](https://xemstudio.com/objects/socket-head-cap-screws-metric/)
- [Hex nuts, M2–M8 (ISO 4032)](https://xemstudio.com/objects/hex-nuts-metric/)